The present invention relates generally to a wideband self mixing millimeter (MM) wave receiver, and more particularly to a receiver combined with a spiral type antenna.
To provide wide band coverage at mm wave frequencies, antenna detectors (antector) and antenna mixers have been pioneered by several engineers. The basic approach of an antenna detector is to use a diode detector mounted at the center of a spiral antenna, which covers a wide frequency range. This kind of receiver is very small in size, but the sensitivity of the receiver is low, typically -30 to -40 dBm. The antenna mixer approach uses a mixer at the center of the spiral antenna. The output of the receiver will be at an intermediate frequency (IF) where an amplifier can be added to improve the sensitivity. Although this approach can improve the sensitivity of the receiver, it also increases the size of the receiver because a local oscillator is needed.
U.S. Patents of interest include U.S. Pat. No. 4,287,603 to Moser, which discloses a radiated input mixer for converting a radio frequency signal to an intermediate frequency signal with the aid of a local oscillator signal. U.S. Pat. No. 4,319,248 to Flam discloses an integrated detector device sensitive over a broad band of frequencies. U.S. Pat. No. 3,246,245 to Turner and U.S. Pat. No. 3,296,536 to Copeland et al each disclose a combined spiral antenna and converter circuit. U.S. Pat. No. 4,368,472 to Ghandi discloses a dosimeter which includes a spiral antenna and a schottky diode. U.S. Pat. No. 3,509,465 to Andre et al discloses a spiral antenna having an amplifier and bias feed circuits integrated therein. U.S. Pat. No 3,949,407 to Jagdmann et al discloses a direct fed spiral antenna element array.